bad request when click on sign-in

[nhung.ng]

I have just integrated SDK into my application, and when click on sign-in, it shows:

"bad_request

Request parameters failed to meet all constraints"

What did I do wrong here? 

[Alitu]

We started encountering this error with our testers today. We found that if they use incognito mode, they are able to login successfully. Even after clearing the cookies / cache in normal mode, they are unable to login.

[Jasonbischoff]

I'm experiencing the same error as well.